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R.M. Clary, Ph.D., F.G.S.
Department of Geosciences
Mississippi State University
CHAPTER 19
PRIMATE AND HUMAN EVOLUTION
OUTLINE
INTRODUCTION
WHAT ARE PRIMATES?
PROSIMIANS
ANTHROPOIDS
HOMINIDS
Australopithecines
PERSPECTIVE Footprints at Laetoli
The Human Lineage
Neanderthals
Cro-Magnons
SUMMARY
CHAPTER OBJECTIVES
The following content objectives are presented in Chapter 19:
 Primates are difficult to characterize as an order because they lack strong specializations
found in most other mammalian orders.
 Primates are divided into two suborders: the prosimians, which include lemurs and
tarsiers, and the anthropoids, which include monkeys, apes, and humans.
 The hominids include present-day humans and their extinct ancestors.
 Human evolution is very complex and in a constant state of flux owing to new fossil and
scientific discoveries.
 The most famous of all fossil humans are the Neanderthals, which were succeeded by the
Cro-Magnons, about 30,000 years ago.
LEARNING OBJECTIVES
To exhibit mastery of this chapter, students should be able to demonstrate comprehension of
the following:
 the characteristics and evolution of the primate groups
 the characteristics of australopithecines and their place in human evolution
 the complexity of human evolution reconstruction
182
R.M. Clary, Ph.D., F.G.S.
Department of Geosciences
Mississippi State University
 the evolutionary history of the genus Homo, including Neanderthals and Cro-Magnons
 the migration of humans on the Earth
CHAPTER SUMMARY
1. The primates evolved during the Paleocene. Several trends help characterize primates
and differentiate them from other mammalian orders, including a change in overall
skeletal structure and mode of locomotion, an increase in brain size, stereoscopic vision,
and evolution of a grasping hand with opposable thumb.
Figure 19.1 Primates
Table 19.1
Classification of the Primates
Enrichment Topic 1. Changing Tectonics, Climate, and Human Evolution
East Africa is one of the most changed landscapes in recent geological history. Tectonic
movements and climate changes influenced the area during the time that humans were
evolving. As the Himalayans were rising, the moist air was sucked from the Indian Ocean to
produce the Southeast Asian monsoons. This deflected moisture away from Africa, drying out
the African continent. The distinct climatic split between Asia and Africa corresponds to the
split between Asian and African apes! The effect of the formation of the African Rift Valley
has also had an effect on evolution. The eastern rift shoulder acted as an impediment to
moisture, causing the area to dry out even further. The topography also changed from a flat
region to a more mountainous region. It is proposed that this change may have caused the
evolution of bipedalism, sometime after 6 million years ago. The effects of tectonism on
human evolution are not restricted to Africa. As the Isthmus of Panama formed, the water
exchange between the Pacific and Atlantic oceans cased. This, in turn, strengthened the Gulf
Stream by pumping more warm water northward, which in turn provided the moisture for the
growth of the Pleistocene ice sheets. How did the drying out of the African continent affect
evolution? Rick Potts hypothesized that during dry periods, hominid brains may have
evolved as a means of dealing with the variable environment. Larger jaws may also have
developed through natural selection so that the early hominids could eat just about anything.
Maslin, Trauth, and Christensen, “A Changing Climate for Human Evolution,” Geotimes,
Sept. 2005, v.50 n.9 p.18-22.
2. The primates are divided into two suborders: the prosimians and the anthropoids. The
prosimians are the oldest primate lineage and include lemurs, lorises, tarsiers, and tree
shrews. The anthropoids include the New and Old World monkeys, apes, and
hominoids, which are humans and their extinct ancestors.
Figure 19.2 Eocene Prosimian
Figure 19.3 Aegyptopithecus zeuxis
Figure 19.4 Proconsul
Figure 19.5 Comparison of Gorilla and Human Locomotion and Hominid Brian
Size
183
R.M. Clary, Ph.D., F.G.S.
Department of Geosciences
Mississippi State University
Enrichment Topic 2. The Last Common Ape Ancestor
A discovery of Pierolapithecus catalaunicus has scientists speculating that it may be the last
common ancestor of the great ape family and humans. Found in Spain, the fragments
recovered indicated that the organism stood approximately four feet tall and weighed 66-77
pounds. Nicknamed Pau, the fossil revealed that the organism had a broad, sloping face and a
wide rib cage, plus a flexible wrist for climbing. The fingers were more monkey-like than
apelike, however. Pau may support the hypothesis that early ancestors of humans evolved in
Eurasia, and migrated back to Africa. “New Limb on Family Tree,” Discover, Feb. 2005,
v.28 n.2 p.9.
3. The oldest known hominoid is Sahelanthropus tchadensis, dated at nearly 7 million
years. It was followed by Orrorin tugenensis at 6 million years, then two subspecies of
Aradipitherus at 5.8 and 4.4 million years respectively. The early hominids were
succeeded by the australopithecines, a fully bipedal group that evolved in Africa 4.2
million years ago. Currently, five australopithecine species are known: Australopithecus
anamensis, A. afarensis, A. africanus, A. robustus, and A. boisei.
Figure 19.6 The Stratigraphic Record of Hominids
Figure 19.7 Sahelanthropus tchadensis
Figure 19.8 Skeleton of Lucy (Australopithecus afarensis)
Figure 19.9 African Pliocene Landscape
Figure 19.10 Australopithecus africanus
Figure 19.11 Australopithecus robustus
4. The Homo lineage began about 2.5 million years ago in Africa with the evolution of
Homo habilis, which survived as a species until about 1.6 million years ago.
Figure 19.12 Homo habilis
Enrichment Topic 3. Europe’s Oldest Hominid
In 2008, the oldest fossil hominid of Europe was found in the form of a jawbone in Spain.
Assigned to the species Homo antecessor, the fossil is approximately 1.2 million years old.
The new find suggests that early humans arrived in Europe sooner that previously
acknowledged. Wright, “Europe’s Oldest Hominid Unearthed,” Discover, January 2009, p.60.
5. Homo erectus evolved about 1.8 million years ago and was the first hominid to migrate
out of Africa. Between 1.8 and 1 million years ago, H. erectus had spread to Europe,
India, China, and Indonesia. H. erectus used fire, made tools, and lived in caves.
Figure 19.13 Homo erectus
Figure 19.14 European Pleistocene Landscape with Homo erectus
Enrichment Topic 4. The Clubbing Wars?
Although Homo erectus appears to be related to the modern human lineage, researchers were
long puzzled over the very unique qualities of the skull. The researchers hypothesized that
the thickening of skull areas was a response to behaviors within the species.
184
R.M. Clary, Ph.D., F.G.S.
Department of Geosciences
Mississippi State University
The skullcap and other features of the skull and jaws indicate that the species was adapted for
defense against trauma. The researchers hypothesized that the patterns witnessed in H.
erectus’ skull evolved in response to interpersonal violence. Even today, some groups
practice intergroup warfare. Why would these features be lacking in modern humans, if H.
erectus represented one of our ancestors? The researchers hypothesized that these features
may have disappeared because cranial bone may have become thinner, just to reduce the
weight of the skull. Boaz and Ciochon, “Headstrong Hominids,” Natural History, Feb. 2004,
v.113. n.1 p.21-34.
6. Sometime between 200,000 and 100,000 years ago, Homo sapiens evolved from Homo
erectus.
7. Neanderthals were not much different from present-day humans, only more robust and
with different shaped skulls. They made specialized tools and weapons, apparently took
care of their injured, and buried their dead.
Figure 19.15 Neanderthal Skull
Figure 19.16 Pleistocene Cave Setting with Neanderthals
Enrichment Topic 5. Neanderthals and Modern Humans
Researchers working at two sites in Gibralter discovered that Neanderthals exploited the food
resources of their coastal environment, and ate seals, dolphins, and fish. They also cooked
mussels. Other studies point to Neanderthals as gifted toolmakers. When Neanderthal and
Cro-Magnon tools were recreated, the Neanderthal tools lasted longer, and wasted less rock
when produced. Although Neanderthal brains developed differently from modern humans,
new discoveries revealed that Neanderthal babies were also born with brains as large as
modern humans. Although the Neanderthals were surprising more similar to modern humans
that previously acknowledged, computational biologist Richard Green published the first
sequence of 38,000 year-old Neathderthal mitochondrial DNA. The sequence indicated that
the split between modern humans and Neanderthals occurred about 660,000 years ago. No
genetic evidence indicates that Neanderthals and modern humans ever interbred. Ruvinsky,
“They’re Just Like Us,” Discover, January 2009, p. 28-29; “Science News of the Year:
Humans,” Science News, January 3, 2009, v. 175, no. 1, p. 18.
8. The Cro-Magnons were the successors of the Neanderthals and lived from 35,000 to
10,000 years ago. They were highly skilled nomadic hunters, formed living groups of
various sizes, and were also skilled cave painters.
Figure 19.17 Pleistocene Cro-Magnon Camp in Europe
Figure 19.18 Cro-Magnon Cave Painting
9. Since the appearance of Cro-Magnons, human evolution has become almost entirely
cultural rather than biological.
185
R.M. Clary, Ph.D., F.G.S.
Department of Geosciences
Mississippi State University
Enrichment Topic 6. The Little People of Flores.
Ever since the diminutive skull and partial skeleton of a tiny human were discovered on the
Indonesian island of Flores, paleontologists have been arguing the identification of the find.
Currently dubbed a new species, Homo floresiensis, the individuals reached the island a
minimum of 38,000 years ago, and survived until 12,000 years ago. An adult female probably
stood 3 feet, 3 inches tall and weighed approximately 35 pounds. Some researchers propose
an early arrival for Flores man on the island, and evolutionary “dwarfing” in which species
evolve into smaller creatures from larger ones. Flores man would have been in existence at
the same time as Homo sapiens, but there is no evidence that the two species ever interacted.
Not all scientists are in agreement with the hypotheses, however, and propose that the fossils
do not represent a new species, but genetic defects that were prevalent in the population. The
debate continues. “Evolutionary Shrinkage,” Science News, Oct. 30, 2004, v.166. n.18 p.
275.; “Encore for Evolutionary Small-Timers,” Science News, Oct. 15, 2005, v.168 p.244245.
In more recent studies of the “hobbit,” Adam Gordon at the University of Albany found that
the skull was “well outside the range of modern human variation.” The size and shape of the
skull are more similar to Homo habilis. William Jungers of Stony Brook University found that
the hobbits’ feet were large in propotion to its body. However, Robert Eckhardt of Penn State
Univeristy claimed that DNA isolated from the remains of the hobbit matches the DNA of
Homo sapiens. Bosveld, “Hobbit Humans: Small Head, Big Feet,” Discover, January 2009,
p. 68.
LECTURE SUGGESTIONS
The Phylogeny of Humans
A 90-minute activity that utilizes the early technique of DNA-DNA hybridization can be used
to illustrate the genetic difference between the human and ape superfamily, Hominoidea.
Complete directions and suggestions can be found in “Building a Phylogenetic Tree, The
American Biology Teacher, Oct. 2004, v.66 n.8 p.560-566.
The Human Factor
1. Discuss with your students which characteristics make an organism “human.”
Although historic delineations between humans and non-humans involved burying of
the dead, using tools, and creative expression, some of these traits have been exhibited
by non-modern humans or other organisms. Which characteristics—other than
physical differences—can be used to illustrate the “human” trait?
2. Evolution proceeds by natural selection, but can natural selection operate in the human
population? What happens to children who are born with genetic abnormalities?
Does the “survival of the fittest” apply to humans? What are the possible ramifications
of this for our species in the future?
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R.M. Clary, Ph.D., F.G.S.
Department of Geosciences
Mississippi State University
3. Remind students that the study of humans transcends two disciplines, physical
anthropology and paleontology. How might these two different types of scientists
approach the topic of human evolution?
The Evolution of Man
A controversial direction to explore in discussion of the evolution of man involves the
discussion of science and religion in human origins. The late Stephan J. Gould wrote
interesting essays that discussed evolution and creation in Bully for Brontosaurus. In "Knight
takes Bishop?" the story of T.H. Huxley is told. Huxley eloquently and effectively challenged
the clergy; he summarized that he would prefer to have an ape than the Bishop for an
ancestor. The story highlights the tremendous emotion that has overpowered—and continues
to overpower—any realistic discussions of evolution in the United States. (It may help your
students to know that Gould was considered to be a spiritual man who also accepted
evolution. His position was that the two realms exist separately and independently from each
other.)
CONSIDER THIS
1. Discuss the emotion that the topic of human evolution inspires in many. Should the
federal government regulate what is taught in the public schools with regards to
evolution?
2. Nothing in science seems to change as much as the identity of our human ancestors.
While those studying human evolution do not doubt that humans and other primates
share common ancestors, the story continually evolves with the discovery of new fossils,
the resultant interpretations, and new techniques of analysis. Discuss with the students
that debates within the scientific community do not show a lack of support for
evolutionary theory or human evolution in general. Are there any subjects within
geology that have not been debated when a new hypothesis was proposed?
3. How do humans affect Earth when compared with other species? Are the impacts for
the benefit or the detriment of the Earth?
187
R.M. Clary, Ph.D., F.G.S.
Department of Geosciences
Mississippi State University
IMPORTANT TERMS
anthropoid
australopithecine
Cro-Magnon
hominid
hominoid
Homo
Neanderthal
primate
prosimian
SUGGESTED MEDIA
Videos
1. Walking with Cave Men, The Discovery Channel
2. L.A. 10,000 Years B.C., The Discovery Channel
3. Search for the First Human: A Secrets of the Dead Special, PBS Home Video
4. The Future is Wild: 5 Million Years Ice World, Discovery Channel
5. Iceman: Cold Case Solved, Discovery Channel
6. Prehistoric America, BBC
7. Living Planet, New Worlds, BBC
8. PaleoWorld, Ape Man, The Learning Channel
9. PaleoWorld, Trail of the Neanderthal, The Learning Channel
10. PaleoWorld, Missing Links, The Learning Channel
11. Life on Earth, The Compulsive Communicators, BBC
12. Miracle Planet, Survival of the Fittest, The Science Channel
13. Secrets of the Dead, The Lost Vikings, PBS Home Video
14. Nature, Triumph of Life: Brain Power, PBS Home Video
15. The Journey of Man, PBS Home Video
16. Mammoths of the Ice Age, NOVA, WGBH Boston
17. The Ape that Took Over the World, BBC
18. History of the Anthropoid: Search for the Beginning, Films for the Humanities and
Sciences
19. Origins of Homo sapiens: East African Roots, Films for the Humanities and Sciences
20. The Story of Hominid Evolution, Films for the Humanities and Sciences
21. Evolution of Human Purpose, Films Media Group
22. Ape to Man, The History Channel
23. Clash of the Cavemen, The History Channel
24. Judgment Day: Intelligent Design on Trial, NOVA, WGBH Boston
25. Ape Genius: What Separates Apes from Humans, National Geographic
26. Boldest Hoax, NOVA, WGBH Boston
27. Human Footprint, National Geographic
28. Journey to 10,000 B.C., The History Channel
29. The Last Great Ape, NOVA, WGBH Boston
30. Walking with Caveman, BBC
Software and Demonstration Aids
1. Neanderthal Man Reconstruction Kit, The Discovery Channel
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R.M. Clary, Ph.D., F.G.S.
Department of Geosciences
Mississippi State University
CHAPTER 19 - ANSWERS TO QUESTONS IN TEXT
Multiple Choice Review Questions
1.
2.
3.
4.
a
d
e
d
5.
6.
7.
8.
b
c
b
e
9.
10.
11.
12.
c
d
a
c
Short Answer Essay Review Questions
13. Prior to the discovery of fossils of Australopithecus anamensis from Ethiopia, the origin
of Australopithecus had been hampered by a sparse fossil record. The discovery of
Ardipithecus in the same region of Africa, at the same time, provided evidence that
Ardipithecus evolved into Australopithecus and links the two genera.
14. Primates have an arboreal, insectivorous ancestry. Evolutionary trends are toward diverse
skeletal modifications, different modes of locomotion, increased brain size, a shift to
smaller and more generalized teeth, stereoscopic vision, and a grasping hand with an
opposable thumb.
15. Compared to Homo sapiens (including Cro-Magnon), Neanderthals had a shorter, more
robust and powerful physique, typical of human adaptation to cold climates. They also
had an elongate skull with a reduced frontal lobe area and extended occipital region,
larger brow ridges, and a receding chin. Their cranial capacity was slightly larger than
that of modern humans, but their brain mass was distributed differently.
16. The genus Homo includes H. habilis, H. erectus, the Neanderthals (H. neanderthalensis
or the alternative, H. sapiens neanderthalensis), and H. sapiens. H. habilis (2.5-1.6
million years ago) was an African form that apparently used tools; the larger, and larger
brained H. erectus spread out of Africa to India, China, and Indonesia. Neanderthals,
found from the Mid-east through western Europe, had a shorter, more robust physique
and flatter skull, more prominent brow ridges, and receding chin compared to later H.
sapiens; many of their physical adaptations seem related to cold climate survival. Early
modern H. sapiens, as exemplified by Cro-Magnon (35,000-10,000), were essentially the
same physiologically as fully modern humans, and had complex culture compared to all
earlier members of the genus Homo.
17. Anthropoids evolved from prosimians in the Late Eocene. In North Africa, rain forests
supported a diverse fauna of prosimians, one of which gave rise to a very similar early
anthropoid. Anthropods are divided into three superfamilies: Old World Monkeys, New
World monkeys, and Hominoids. The Hominoids evolved, and consist of three families:
the great apes, the lesser apes, and the hominids, which represent humans and their
ancient ancestors.
189
R.M. Clary, Ph.D., F.G.S.
Department of Geosciences
Mississippi State University
18. Hominids include humans (Homo) and their extinct ancestors. Their fossil record extends
back about 7 million years. The hominids are distinguished by several features, including
bipedalism, large and internally reorganized brains, reduced faces, reduced canine teeth,
omnivorous feeding, increased manual dexterity, and use of sophisticated tools. There is
no clear consensus on the evolutionary history of hominids. However, the oldest hominid
known is Sahelanthropus tchadensis, which existed near the time that hominids diverged
from the chimpanzees. This organism exhibits a small brain case and chimp-like teeth,
but it was probably bipedal, and had a flat nose and brow ridges. Later, the genus
Ardipithecus evolved, followed by the genus Australopithecus. Finally, the genus of
modern humans, Homo, evolved. Hominids share the hominoid superfamily with great
and lesser apes.
19. Prosimians are the lower primates and include lemurs, tarsiers, lorises, and tree shrews.
They are small, arboreal, mostly nocturnal, and closely resemble their Paleocene roots.
Anthropoids are the higher primates and include monkeys, apes, and humans. They are
larger, smarter, more diverse, and more derived primates; they arose in the Late Eocene.
20. According to the “out of Africa” view, early modern humans evolved from a single
woman in Africa, whose offspring then migrated from Africa, perhaps as recently as
100,000 years ago, and populated Europe and Asia, driving earlier hominid populations
to extinction. The supporters of the “multiregional” view contend that early modern
humans did not have an isolated origin in Africa but established separate populations
throughout Eurasia. Occasional contact and interbreeding between these populations
enabled our species to maintain its overall cohesiveness while still preserving the regional
differences in people we see today.
Apply Your Knowledge
1. There may be many different student views with this question. However, given that
human evolution does not necessarily operate according to natural selection, changes in
the human population are not necessarily driven by the “survival of the fittest.”
Technological advances allow us to keep those individuals with genetic abnormalities
alive, when they would have died in the past. From a human standpoint, this may be a
morally good thing. However—as most microbiologists would concur—this is not a good
thing for evolution! As individuals with genetic flaws mature, they are able to reproduce,
perpetuating less-than-desirable genes in the population. With technological advances,
the removal of “bad genes” from DNA may one day be a possibility. Recently, a baby
was born which was genetically selected not to have a cancer gene. Will parents be able
to code for various traits of their offspring? Will the population become skewed toward
certain characteristics (sex, hair color, eye color, height, body shape) that people deem
“desirable?” The moral and genetic implications of this type of technology will be great,
and it may not lead to diversity in the next 5000 years if all parents desire the same traits
for their children.
190
R.M. Clary, Ph.D., F.G.S.
Department of Geosciences
Mississippi State University
2. Student answers will vary greatly. Some students may take a very broad “history of life”
view, and trace human evolution from the first vertebrates (fish), to amphibians, reptiles,
mammal-like reptiles, mammals, primates, anthropoids, hominoids, hominids, through
Homo sapiens. Other students may choose to focus upon more recent hominids,
especially the Neanderthals, who resembled Cro-Magnons in most features. Evolution
since the appearance of Cro-Magnons has been largely cultural, and some students may
focus upon that.
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